(1 point) A physicist wants to estimate the rate of emissions of alpha particles from a certain source. He counts 400 emissions in 80 seconds. Estimate the rate, in emissions per second and find the uncertainty in this estimate.

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm

Asap i'm in class rn a 1,000-kg car is traveling 20 m/s on a flat stretch of road. it gets to a hill and coasts uphill until it stops. how high up the hill does the car travel? givens: equation: 1/2mv2initial=mghfinal solve for h. plug & chug, label.

The substances that are necessary for producing of certain hormones and that store and transport vitamins